Radio signaling system



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ORNEY E. BELLINI RADIO SIGNALING SYSTEM Filed Oct. 24, 1924 INVENTOR TTOR B Dec. 17, 1929.

Patented Dec. 17, 1929 UNETEE STATES ETTORE BELLINI, OE PARIS, FRANCE RADIO SIGNALING SYSTEM Application filed October 24, 1924, Serial No.

As is well known the radio-goniometer is a device used in wireless telegraphy and telephony, the purpose of which is to turn or changee the direction of the transmission or the direction in which waves are received, the said levice, in this latter case, making it possible to determine the direction of a sending station.

Two types of radio-goniometer are known, i. e., the magnetic radio-goniometer Bellini- Tosi, and the electric radio-goniometer type Bellini. These devices, on the one hand, are united with two directional aerials disposed cross-fashion, and, on the other hand, with the receiving devices (amplifiers, detector, etc.) or wave generators.

The radio-goniometer forming the subjectmatter of the present invention is adaptable both to transmission and receiving work, although it really deserves interest only in connection with receiving wireless waves.

When damped waves were used, it was customary to tune by the aid of two variable condensers the two aerial wires of the directional kind connected with the radio-goniometer. Nowadays, however, when the use of continuous waves has become well nigh the general rule, the tuning of the two aerials has become a very delicate task. To obviate the difliculties in this respect, it has been suggested to use aperiodic frames or loops which are coupled as closely as feasible with the detector-amplifier system. But this means a loss in range. The two aerials must be as similar as possible, and to achieve this, inductance coils and convenient resistances are inserted. However, in cases in which the two aerials difier very widely from one another, it is no longer possible to render them identical, at least not for all wave-lengths. The conditions of resonance will then vary upon revolving the mobile part of the radio-goniometer, and no finding of direction is feasible any longer. The situation becomes still worse if the receiving system is worked on the autodyne principle in connection with the reception of continuous waves, since the note changes upon the movable member of the radio'goniometer being turned, indeed, the sound may even go beyond the limits of audi- 7%,551, and in France November 24, 1923.

bility. In this manner additional zero points might be found, and this naturally would lead to errors in fixing the direction of the sending station.

The case of two widely difierent directional aerials arises, e. g., in the operation of aeroplanes. The use of a single revolving loop, system Blondel, with the possible exception of very large craft, is well nigh impossible. It has also been suggested pre- 7 viously to equip aeroplanes with but one loop or coil antenna constituted by a conductor secured onto the carlins outside; however, in this case the taking of bearings makes it necessary for the aeroplane to go through 5 maneuvers incompatible with its normal travel.

The ideal thing for aeroplanes would be a radiogoniometer system comprising two crossed frames or coils, one of which to be cemented onto the carlin, and the other one to the wings and the uprights connecting the two wings, a plan that does not involve much space, is extremely light, and independent of the travel of the aeroplane. But it is just under conditions as just described that the two coils, though realizable, are of necessity Widely different in view of the very different shapes and dimensions of the wings and the carlin. The electric and the magnetic radiogoniometer are only poorly adapted to this special purpose.

Now, the radio-goniometer forming the subject-matter of this application obviates this inconvenience. In the accompanying drawing, Fig. 1 is a diagrammatic showing of the radio-goniometer, Figs. 2, 3, and 4 are reception diagrams of this radio-.goniometer, and Fig. 5 is a modification showing a con tainer for using a liquid potentiometer'in- 9o stead of the wire shown in Fig. 1. Substanti ally it comprises, as can be seen from Fig. 1,

a circumference consisting of a resistance wire, or, better still, a line of graphite l, 1, 1, 1, arranged or drawn on an insulating surface, 95 and provided with four taps or contacts, 2, 2, 2, 2, displaced by an angle of 90 degrees with relation to one another. The ends of each directional antenna are connected with two diametrically opposite contacts. Two

cont-acts 3, 3, located diametrically opposite one another and insulated from one another are arranged on an arm which is capable of being turned by the aid of a knob these contacts serve to establish connection with the amplifier-detector, or else with the apparatus adapted to generate waves incase of the eqipment being used for sending.

The E. M. F .s induced in the antennae by the electromagnetic field set up in these aerials and in the circuit 1, 1, 1,1, currents whose intensities will be proportional to theE. Ma

a two maximum and two minimum values or zeros. The shapes of the curves-giving the variations of the potentials, however, will be different compared with the sinuous characteristics of the magnetic and electric radiogoniometer. They will be triangular (Fig.

2) when the sending station happens to be;

located in the plane of one of the coils, trapezoidal (Fig. 3) in shape when the sending station is at an angle of 45 degrees, and of the form shown inFig. 4c,'more or less distorted, in other cases. i

The zero point will be in a direction perpendicular to the direction of sending of they transmitting station when the latter is at O. 45, 90, 135, 180, etc, degrees, a knownyangle being formed with reference to the direction of thetransmitting station Whenever this direction is intermediate between those hereinbetore indicated.

Instead of making the radio-goniometer of 'a Wireor a graphite line, it could, as shown in Fig. 5, alsobe formed of a container or vessel 10, made either ofconducting or insulating material, and containing a liquid 20 possessing convenient conducting powers, four plates (or metallic wires) fixed at 90 degrees with relation to one another, 30, 30, 30, 3O united with the two coils, and a rotary system of two plates or. wires 50, 50, connected with the receiving apparatus, or in case of sending, tothe high frequency waves generator. The said plates may be either cylindrical or'flat as in the electric radiogoniometer, and may have special shapes, with the end inview of obtaining potential-difl erence variation curves of predetermined shape.

Claims: i 1. In a radiogoniometer system, the combination with a pair of fixed aperiodic loop aerialsdisposed at right angles to each other, of a closed resistance member connectedto all the aerial terminals in such manner that each loop aerial circuit has included therein a pair of branched portions, of said resistance, and

an adjustable member cooperating with said resistance member for determining from the position of said adjustable member the line I of direction of a transmitting station.

2. In a radiogoniometer system, the combination with'a closed potentiometric resistance, of a pair o f-fixed directional loops, each connected to diametrically opposite points of said resistance, and a rotatable slider associated with said resistance, the direction of a distant transmitting station fromwhich signals are received by the loops having a definite angular correspondence with the position of the slider giving minimum or maximum reception.

3. Ina radiogoniometer system, the combination with a closed potentiometric resistance, of a pair'of fixed aperiodic loop aerials disposed at right angles to each other and each connected to diametrically opposite points of said resistance, a rotatable slider contacting at diametrically opposite points of said resistance, and signal responsive means connected to said slider,'the arrangement being such that the intensity of received signals is determined by the position of the slider, said signal intensity passing through two min ima and two maxima values for a complete rotation of the slider.

4. Ina directional radio receiving system, a plurality o1": fixed loops, a resistance asso ciated with said loops, and a rotatable member associated with said resistance, and adapted to control the intensity of the incoming signal, the position of the rotatable member being in predetermined angular relation with respect to the signal transmitting station for a given signal intensity.

ETTORE BELLINI. 

